Effect of Fluconazole, Clarithromycin, and Rifabutin on the Pharmacokinetics of Sulfamethoxazole-Trimethoprim and Dapsone and Their Hydroxylamine Metabolites

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To determine the effects of fluconazole and either rifabutin or clarithromycin, alone and in combination, on the pharmacokinetics of first sulfamethoxazole-trimethoprim and then dapsone in HIV-infected patients.

Although prophylaxis for more than one opportunistic infection is emerging as a common clinical practice in patients with advanced HIV disease, little is known about possible adverse drug interactions. The need exists to define pharmacokinetics and pharmacodynamic adverse interactions of the many combination prophylactic regimens that may be prescribed.

Although prophylaxis for more than one opportunistic infection is emerging as a common clinical practice in patients with advanced HIV disease, little is known about possible adverse drug interactions. The need exists to define pharmacokinetics and pharmacodynamic adverse interactions of the many combination prophylactic regimens that may be prescribed.

In Part A, patients receive sulfamethoxazole-trimethoprim (SMX/TMP) alone for 2 weeks, then in combination with fluconazole, rifabutin, or both drugs, each over 2-week periods in a randomly assigned order. Patients in Part B receive the same regimens except with clarithromycin substituted for rifabutin. In Part C, patients receive dapsone alone for 2 weeks, then in combination with fluconazole, rifabutin, or both drugs in the same manner as in Part A. Part D patients receive the same regimen as those in Part C, except with clarithromycin substituted for rifabutin. Patients are followed every 2 weeks.

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Ages Eligible for Study:

18 Years to 65 Years (Adult)

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria

Concurrent Medication:

Allowed:

Antiretroviral therapy provided patient has been on a stable dose for at least 4 weeks prior to study entry.

Methadone for drug abuse programs provided patient has been on a stable dose for at least 4 weeks prior to the study.